Iodine deficiency remains a global nutritional public health challenge, with evidence suggesting borderline adequate or even deficient status for UK and Irish subpopulations such as schoolgirls and pregnant women. The solution, according to the WHO, is salt iodisation, but it is not known how widely available iodised salt is in supermarkets. Iodised salt availability was determined by a shelf survey of 89 supermarket stores on the island of Ireland (n = 30 in Northern Ireland and n = 59 in the Republic of Ireland) from September 2018 to January 2019, to take into account factors such as store type, location, population density, socioeconomic status and ethnicity. Availability was calculated as the number of stores selling iodised salt as a percentage of the total. Iodised salt was only available in 11 stores (12%), of which 10 were ethnic stores. This indicates a lack of access for the majority of the Irish and Northern Irish populations.